Off The wall

Despite their name, wallflowers can shine in pots too – and now’s the time to plant them for a vibrant spring display, says Monty Don

Biennials have adapted to survive the harshness of winter before restarting growth and flowering early in the new year, so now is the ideal time to plant them. biennials we use most here are wallflowers. The basic wallflower has yellow flowers and will seed itself and grow enthusiastically in apparently solid walls and stone – hence the name. They like good drainage and suffer badly if they sit all winter in wet ground, so I add extra grit to my rich Herefordshire loam.

wallflowers are very hardy, it’s a good idea to pinch out the growing tips when you plant them to create bushy plants, and to remove any late, vigorous growth that can be hit by an early frost. It’s a mistake to over-feed the soil, which will contribute to this late spurt of growth; and never give them fertiliser. The poorer the conditions, the longer they will last, and they can keep going happily for five years or more (some wallflowers are, in fact, perennials).

Many wallflowers are sterile hybrids so you can only get new plants by taking cuttings from them – or buying more seed – but many others seed themselves easily. You do not need a greenhouse to grow them – planting a line or two in a seed bed in the vegetable garden is fine. Sow seeds in late spring or early summer, then grow on and plant out now. Thin them initially to about 2.5cm or so apart, and then again to 15cm, transplanting the thinnings to another line. When I was a child they were as regular a presence in our vegetable garden as carrots or peas.

There are three groups of erysimum varieties of wallflower. My favourite plant of all of these, E. cheiri ‘Blood Red’, comes from the tallest group, which has 12 colours. The Bedder Series is much shorter

Erysimum cheiri and compact, with flowers in four hues: bright yellow, primrose, orange and scarlet. You are likely to find these as a random mixture but they can be bought as individual colours. If you’re going to grow them in containers, choose the Prince Series, which are the shortest varieties. They come from Japan in five colours, but again, you’re likely to buy them as mixed colours. We have Erysimum ‘Bowles’s Mauve’, which flowers from March until June and is a really good addition to a border.

Although wallflowers are easily raised from seed, you can also buy them as small, lush plants. They behave like shrubs, with a tendency to sprawl, so plant them close together to support each other. Each plant produces flowers sporadically and you need the massed effect to make the most of the colour.

Tulips are the traditional accompaniment to wallflowers and they work well together, flowering at around the same time, the tall goblets of tulip rising above the massed foliage of the wallflowers. Always plant wallflowers first, otherwise half the tulip bulbs will be chopped up by your trowel as you go. Tulips should be placed in the ground now, and when you do this, just dot the bulbs in among the wallflowers.

Wallflowers are brassicas, and so are liable to suffer all the problems of the humblest cabbage – sooner or later they will get a virus, or clubroot, or grey mould, or some such disaster. But sow fresh seed every year and you will have a healthy new batch ready to take their place.

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At this time of year, salads from the garden are a precious treat – and one that I try to enjoy every day. This takes some organising with choosing the right plants, and radicchio is invaluable. It is beautiful too, adding a deep carmine to a salad bowl.